Conventional electrical outlet sockets of standard dimension and configuration are ubiquitous in North America. Generally, such electrical components are affixed in electrical boxes attached to the wall studing so that the outward facing side of the box is approximately flush with the surface of the wall. The outlet most commonly found in North American buildings is a "duplex receptical" (i.e., double outlet) having two faces, each having a characteristic profile generally described as circles cut by parallel cords to give the appearance of rectangles having two opposite rounded ends.
A plate designed to cover such outlets naturally has (in this example) two holes corresponding in size and position to the faces of the outlets. Thus, placement of the cover plate on the wall over the box shields all the unsightly elements of the outlets to provide an attractive finish while allowing access to the outlet sockets. The duplex reciprocal is provided with a standard screw hole in alignment with a corresponding hole in the cover plate. The position of this hole is fixed for a given component. For instance, in the case of a duplex outlet, the screw hole is always centrally positioned equidistant from each hole.
One of the problems encountered by interior designers seeking to modernize or somehow alter the outward appearance of such standard electrical installations, is that the existing infrastructure of the electrical components is so established as to impead substantial design changes to the installation itself. The only viable alternative is to modify the visible portions only of the fixtures in question. In this regard, it has recently become possible to make use of colored cover plates so that a designer may incorporate (for instance) a red duplex reciprocal to suit a room having a red carpet. Unfortunately, in such cases, the "rounded-rectangular" faces of the outlets (being part of the component's infrastructure) remain visible in their original color (usually only brown, green or white) even when a cover plate of different color has been applied. Even if it were possible to obtain a variety of colored duplex reciprocals, changing the color would involve total replacement of the reciprocal, a time-consuming, skilled and expensive operation.
It is clear, therefore, that there is a need to find a means for covering existing interior electrical components in a way which makes use of the existing electrical infrastructure while occluding those portions (normally visible) which would conflict aesthetically with a cover plate of different color or design.
Although various electrical outlet cover plates have been proposed to provide the interior designer with flexibility and aesthetics, many of the proposed designs have been relatively large, so as to cover the entire outlet and/or incorporate complex mechanisms such as doors or hindged panels manually operable between a closed position in which they hide the face of the outlet, to an open position to expose the outlet face for its intended use. A typical such design is described in U.S. Pat. No. 4,914,265 to Francois Mongeau which describes a cover assembly including a pair of manually operable sliders mounted to a front surface of a cover plate. In a design specifically intended for applications with duplex recepticals, the '265 patent describes a cover plate assembly including a cover plate having two standard orifices, one for each outlet and having a standard central screw hole, registerable with the standard screw hole in the outlet unit as well as a slider mounted over each orifice on the front surface of the cover plate, each slider being moveable, relative to the central screw hole, from a proximal to a distal rectilinearly interchangeable position, the orifices being closed when the sliders are at the proximal positions and open at their distal positions. Both the cover plate and sliders define a series of guide surfaces. Finally, a clip retains the guide surfaces in a cooperating relationship to allow guided, reversable, rectilinear displacement of each slider in a plane parallel to the plate from the proximal position to the distal position.
Although devices such as that described in the '265 patent offer aesthetic flexibility independent of the industry dictated infrastructure of electrical recepticals and is of moderate cost, it shares the shortcomings of other prior art designs inasmuch as it is relatively large and obtrusive, extending a substantial distance away from the wall. In a related problem, such cover plates can interfere with the placement of furniture, foot traffic or the like. Lastly, although representing a cost improvement over earlier designs, the cover plate of a '265 patent is still relatively expensive as contrasted with conventional stamped metal or molded plastic cover plates and can be susceptible to damage such as through movement of furniture which could defeat its aesthetic and safety qualities.
A separate but related problem in the design of cover plates for electrical outlets involves providing a degree of child-resistance or limited access to the underlying electrical circuit. Many prior designs have been proposed to control access to the associated electrical outlet. Most typically, a pronged structure, formed of electrically insulating material is provided which can be inserted into the electrical outlet to prevent inadvertent placement of an electrically conductive instrument by a child or unauthorized individual. Such approaches tend to be easily overcome or defeated by simple removal of the temporary insert. Also, the inserts tend to be either loose or connected to the associated cover plate by a flexible tether, such as described in U.S. Pat. No. 4,801,271 to Danny A. Piper to prevent loss thereof. However, such approaches are deemed aesthetically unacceptable for many applications. Furthermore, the flexible tether of many designs tends within a relatively short period of time to imbrittle and fail, exacerbating the limited aesthetic appearance of the cover plate assembly.